Power lopping shears



Aug. 1 2, 1958 w. D. SCHOFIELD ET AL POWER LOPPING' SHEARS 'Filed May15, 1954 3 Sheets-Sheet 1 INVENTOR. WARNER o. SCHOFIELD EDWIN F- KOCH QROBERT L- SCHOFIELD ATTORNEYS 12, 1958 w. D. SCHOFIELD ET AL 2,846,765

POWER LOPPING SHEARS 3 Sheets-Sheet 2 Filed May 13, 1954 v OE INVEN TOR.WARNER D- SOHOFIELD EDWIN F. KOCHOFIELD BY ROBERT L. SCH

ATTOR N EYS POWER LOPPING SHEARS 5 Sheets-Sheet 3 W. D. SCHOFIELD ET ALAug. 12, 1958 Filed May 13, 1954 M. T F N 0E w 0 m J m 2. n. m mmw M h N8 \nwh r .T Yd? I E. Y B 5 E. m .m 2. 2. Nb 5 .m om u... I mm -WHHH WH Mo h. N H I 5. 3 T 3 8 5 ow 6m vw mm United States Patent POWER LOPPINGSI-[EARS Warner D. Schofield, Edwin F. Koch, and Robert L. Schofield,Westlake, Ohio Application May 13, 1954, Serial No. 429,556

8 Claims. (Cl. 30-228) 7 manipulates the tool from one cutting positionto the next. Such prior shears also tend to jolt or jar unlessdeliberately operated slowly and at low power or pressure. Such joltingor jarring is tiring and aggravates the enervating effect ofcontinuously manually supporting the weight of the actuating mechanism.

We have provided a power shear of the type described which operates fromany tractor power take-01f, thus avoiding the original cost andmaintenance expense of hydraulic or pneumatic compressors and thelike. Aparticular advantage of the invention is that the weight of the cuttingend is minimized because the shear actuating or drivingmeans issupported directly on. the base frame or bed of the mechanism. Further,the operation is such that there is no jolting or jarring when theshears are actuated; in fact, the operation is so smooth that, unlessthe operator watches the actual cut, it is diflicult for him todetermine whether he is trimming wood rather than cutting through emptyair.

These and other objects and advantages of the invention will becomeapparent from the following description of one specific embodiment ofthe invention, together with the accompanying drawings, in which:

Figure 1 is a side viewof an actuating drive used in the illustratedembodiment of the invention.

Figure 2 is an end view of the mechanism shown in Figure l. 1

Figure 3 is a section taken on line 33 in Figure 1.

Figure 4 is a section taken on line 4-4 in Figure 1.

Figure 5 is a view of a shearing head used in the illustrated embodimentof the invention.

Figure 6 is a view in cross-section and on an enlarged scale showing oneof the details of the structure illustrated in Figure 5.

Figure 7 is a view in cross-section on a still larger scale showinganother detail of the structure illustrated in Figure 5.

As shown in the drawings, the base or frame of the mechanism maycomprise suitable channels 10 adapted to be rigidly mounted withstandard U-bolts to a tractor draw bar and having their outer endsjoined by a plate or bed 11. A support 12 extends from the base or frameand adjustably supports a bearing block 13 which, in turn, supports thefree end of a power take-off extension shaft 14 which is splined to thepower take-off shaft 15 of the tractor on which the unitis. mounted. Theextension shaft 14 may include a universal coupling 16 ICC to compensatefor any misalignment with the power takeoff shaft 15.

The bearing blocks 19 and 20 on the plate 11 support the shaft 22 whichextends through a standard one-revolution clutch which may be of theHilliard type, the clutch being generally indicated at 23. The clutchsprocket 24 is coupled by a chain 25 to a drive sprocket 26 keyed to theextension shaft 14. The trip lever. 27 (see Figure 3) of the clutch iscoupled by a link 28 to anactuating solenoid 29, the lever 27 beingbiased into normally extended clutch deactivating position by the spring30.

The shaft 22 is coupled to a shaft 31 through the spur gears 32 and 33,the shaft being mounted between the bearing blocks 20 and 34. The gearratio through this coupling is preferably 1:2 for reasons which willappear below. Keyed on the shaft 31 is a hold-out cam 35 (see Figure 4)which is engaged by a cam follower arm 36 mounted on a small shaft 37which is mounted on the base of the block 20 and which carries at itsopposite end a bell crank 38 (see Figure 3). The bell crank 38 iscoupled to the clutch trip lever 27 by a connecting link 39. The bias ofthe spring 30 keeps the follower arm 36 in following engagement with thehold-out cam 35.

An outrigger support arm extends from the frame or base of themechanism; A slotted anchor plate 46 fixed to the outer end of the arm45 supports a push-pull cable unit comprising an outer flexible sheath47 and an inner push-pull cable 48. At the anchor plate 46, the sheath47 terminates in a sleeve 49 which is threadedly engaged and clamped inposition by the mounting nuts 50. The end 51 of the sleeve 49 comprisesthe socket half of a ball and socket joint. The suitably formed end of asleeve 52 forms the ball half of the ball and socket joint. The sleeve52 is received in a sleeve 53 in which it slides in telescopingengagement. The sleeve 53 is fixed to the terminal fitting of the cable48 which, in turn, is fixed to a terminal link 54. The terminal link 54is pivoted to a drive crank 55 keyed on the end of the shaft 31.

The push-pull cable unit comprising the outer flexible sheath 47 and theinner push-pull cable 48 may extend any desired distance to the shearinghead shown in Figure 5, a good working length being about 20 feet. Thehousing or handle of the shearing head may comprise coaxial tubes and 61which are joined by a swivel connection indicated at 62. Figure 7. is afragmentary section taken in the plane of the paper in Figure 5 in thevicinity of the swivel connection 62. Flanged end inserts 63 are fixedin the ends of the tubes 60 and 61, the flanges being held in slidingabutting relation by a split collar 64 which is held in clampingposition by the bolts 65 (Figure 5). The sheath 47 terminates in asleeve 66 which is threadedly engaged with a pair of nuts 67 which aretightened against an endplate 68. The endplate fits through transverseslots cut on opposite sides of the tube 60', the endplate center beingnotched to accommodate the portion of the tube 60 between the transverseslots. The cable 48 extends through the sleeve 66' and is anchored to arod 69 which extends through the tube 60 and swivel connection 62 and isbolted to a stiff strap 70. At the opposite end of the strap 70, anactuating rod 71 is fixed by a ball bearing swivel connection shown indetail in Figure 6. The outer raceway sleeve 72 is held in seatedposition against the end of the strap by a ring 77 welded to the strapas shown. The inner raceway sleeve 73 is clamped between the nuts 74which are anchored by the locking nuts 75 as shown. Relatively lightcompressive loads may be carried through the split retaining ring 76 ordirectly from the outer nut 74 to the end of the strap 70, depending onthe length of the inner raceway sleeve 73.

The opposite end of the actuating rod 71 passes out 3 the end of thetube 61 and is linked to the pivoting knife of the shear. The fixedknife of the shear is mounted beyond the end of the tube 61 as shown inFigure 5.

Mounted on the tube 60 is a switch 80. The switch leads 81 are securedalong the sheath 47 by suitable clamps. The leads 81 are in acircuitfrom the tractor battery to the switch 80, then to the solenoid28 and then to ground on the frame of the mechanism, as clearlyindicated in Figure 1. The leads 81 may be provided with quickdisconnects 82 and may be enclosed in a common jacket as indicated at83.

At the idling speed of an average tractor, momentary closing of theswitch 80 will cause the mechanism to complete one cutting cycle inapproximately one second, which provides a desirable cutting speed.Naturally, slight variations in tractor R. P. M. may be made if desiredin order to obtain a corresponding change in cutting speed. For example,doubling the tractor R. P. M. will cause the unit to complete a cuttingcycle in approximately one-half second, this faster cutting rate beingpreferable in many instances.

The clutch sprocket 24 is constantly driven through the directly coupledlinkage leading from the tractor power take-ofi 15. When the switch 80is closed, the solenoid 28 is actuated and momentarily withdraws thetrip lever 27. The clutch is thereupon released to transmit power fromthe sprocket 24 to the shaft 22. The shaft 22 drives the shaft 31through the spur gears 32 and 33. As the shaft 22 completes onerevolution, the cam follower arm 36 is engaged with the high portion ofthe cam 35, thus holding the trip lever 27 in withdrawn position torelease the clutch for an additional revolution of the shaft 22. On thecompletion of the second revolution of the shaft 22, the shaft 31completes one full revolution, the cam follower arm 36 is in engagementwith the low portion of the cam 35 having thereby allowed the trip lever27 to be urged into clutch engaging position by the spring 30, and powertransfer from the sprocket 24 to the shaft 22 is thereupon terminated asthe radial face of the clutch trip cam a contacts the trip lever 27.

During the single revolution of the shaft 31, the cable 48 isreciprocated through one pull-push cycle by the drive crank 55. Anytendency of the throw of the drive crank 55 to cause whipping of thepush-pull unit is overcome by the rigid non-pivoting mounting of thesleeve 49 on the anchor plate 46, lateral throw of the driven end of thepush-pull unit being accommodated by the ball and socket joint at 51.Since the length of the flexible sleeve 47 remains substantiallyconstant, the shearing head assembly remains spaced a constant distancefrom the anchor plate 46 along the push-pull unit. The shearing headassembly is thus anchored against relative reciprocating movement of thecable 48, rod 69 and rod 71.

Accordingly, a full revolution of the shaft 31 caused by momentaryactuation of the switch 80 is accompanied by one closing and re-openingof the shears. The swivel connections in the shearing head assemblyenable the operator to freely turn the shears to any desired anglewithout the necessity of twisting the push-pull unit which may beparticularly difiicult to maintain in twisted position during actuation.It will be apparent that the shearing head assembly constitutes a lightand compact unit. These attributes are particularly apparent when thepressent type of shearing head is compared to the shearing heads of theprior art which include fluid motors that have to be carried by theoperator and which buck or jerk when actuated.

Many alternatives to the specific embodiment disclosed above arepossible. For example, the reduction gearing between the output side ofthe clutch and the drive crank may be eliminated and the clutch employedas a true single revolution clutch (cutting action then being more rapidat a given engine speed), although it appears that the illustratedembodiment minimizes clutch wear and strain and appears preferable atthe present time. Ac-

cordingly, the scope of the invention is not to be restricted to thedetails of the illustrated embodiment but is to be defined by the scopeof the following claims.

What is claimed is:

1. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, an anchor block fixedly supportedon said frame, a push-pull unit comprising an outer flexible sheathcapable of resisting substantial axial compression without buckling, andan inner cable loosely received in said sheath, one end of said sheathterminating in a sleeve, means on said anchor block restraining saidsleeve against axial shifting with respect to said frame, one end ofsaid cable passing through said sleeve and extending toward said crankarm, means connecting said one end of said cable to said crank arm forreciprocation of said cable by said crank arm, a shearing head assemblyremote from said frame, theopposite end of said sheath being fixed toone end of said shearing head assembly, lopping shears comprising a pairof scissors, one blade of said pair being fixedly mounted on theopposite end of said shearing head assembly, the opposite end of saidcable having extension means extending through said shearing headassembly and operatively attached to the other blade of said pair, drivelinkage means to drive said shaft, said drive linkage means comprisingcontinuously driven means, clutch means between said continuously drivenmeans and said shaft, solenoid means on said frame, and meansoperatively connected to and controlled by said solenoid means to engagesaid clutch means for one rotation of said shaft upon actuation of saidsolenoid means and to disengage said clutch means upon completion ofsaid one rotation in the absence of continued actuation of said solenoidmeans, switch means on said shearing head assembly to control actuationof said solenoid means, means operatively connecting said switch meansand said solenoid means, said shearing head assembly comprising tubemeans, said cable extension means extending axially through said tubemeans, and swivel connections in said shearing head assembly to enableswivelling movement of said opposite end of said shearing head assemblywith respect to the portion of said push-pull unit extending betweensaid anchoring block and said shearing head assembly.

2. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, an anchor block fixedly supportedon said frame, a push-pull unit comprising an outer flexible sheathcapable of resisting substantial axial compressive stresses withoutbuckling, and an inner cable loosely received in said sheath, one end ofsaid sheath terminating in a sleeve rigidly fixed to said anchor block,one end of said cable passing through said sleeve and extending towardsaid crank arm, means connecting said one end of said cable to saidcrank arm for reciprocation of said cable by said crank arm, a shearinghead assembly remote from said frame, the opposite end of said sheathbeing fixed to one end of said shearing head assembly, lopping shearscomprising a pair of scissors, one blade of said pair being fixedlymounted on the opposite end of said shearing head assembly, the oppositeend of said cable having extension means extending through said shearinghead assembly and operatively attached to the other blade of said pair,drive linkage means to drive said shaft, said drive linkage meanscomprising continuously driven means, clutch means between saidcontinuously driven means and said shaft, solenoid means on said frame,and means operatively connected to and controlled by said solenoid meansto engage said clutch means for one rotation of said shaft uponactuation of said solenoid means and to disengage said clutch means uponcompletion of said one rotation in the absence of continued actuation ofsaid solenoid means, switch means on said shearing head assembly tocontrol actuation of said solenoid means, means operatively connectingsaid switch 5 means and said solenoid means, said shearing head assemblycomprising tube means, said cable extension means extending axiallythrough said tube means, and swivel connections in said shearing headassembly to enable swivelling movement of said opposite end of saidshearing 'head assembly with respect to the portion of said pushpullunit extending between said anchoring block and said shearing headassembly.

3. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, a push-pull unit comprising anouter flexible sheath capable of resisting substantial axial compressionwithout buckling, and an inner cable loosely received in said sheath,one end of said sheath terminating in a sleeve, means on said framerestraining said sleeve against axial shifting with respect to saidframe, one end of said cable passing through said sleeve and extendingtoward said crank arm, means connecting said one end of said cable tosaid crank arm for reciprocation of said cable by said crank arm, ashearing head assembly remote from said frame, the opposite end of saidsheath being fixed to said shearing head assembly, lopping shearscomprising a pair of scissors, one blade of said pair being fixedlymounted on said shearing head assembly, the opposite end of said cablehaving extension means extending through said shearing head assembly andoperatively attached to the other blade of said pair, drive linkagemeans to drive said shaft, said shearing head assembly comprising tubemeans, said cable extension means extending axially through said tubemeans, and swivel connections in said shearing head assembly to enableswivelling movement of said opposite end of said shearing head assemblywith respect to the portion of said push-pull unit extending betweensaid anchoring block and said shearing head assembly.

4. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, an anchor block fixedly supportedon said frame, a push-pull unit comprising an outer flexible sheathcapable of resisting substantial axial compression without buckling, andan inner cable loosely received in said sheath, one end of said sheathterminating in a sleeve, means on said anchor block restraining saidsleeve against axial shifting with respect to said frame, one end ofsaid cable passing through said sleeve and extending toward said crankarm, means connecting said one end of said cable to said crank arm forreciprocation of said cable by said crank arm, a shearing head assemblyremote from said frame, the opposite end of said sheath being fixed toone end of said shearing head assembly, lopping shears comprising a pairof scissors, one blade of said pair being fixedly mounted on theopposite end of said shearing head assembly, the opposite end of saidcable having.extension means extending through said shearing headassembly and operatively attached to the other blade of said pair, drivelinkage means to drive said shaft, said drive linkage means comprisingcontinuously driven means, clutch means between said continuously drivenmeans and said shaft, solenoid means on said frame, and meansoperatively connected to and controlled by said solenoid means to engagesaid clutch means for one rotation of said shaft upon actuation of saidsolenoid means and to disengage said clutch means upon completion ofsaid one rotation in the absence of continued actuation of said solenoidmeans, switch means on said shearing head assembly to control actuationof said solenoid means, and means operatively connecting said switchmeans and said solenoid means.

5. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, a push-pull unit comprising anouter flexible sheath capable of resisting substantial axial compressivestresses without buckling, and an inner cable loosely received in saidsheath, one end of said sheath terminating in a sleeve rigidly mountedon said frame, one end of said cable passing through said sleeve andextending toward said crank arm, means connecting said one end of saidcable to said crank arm for reciprocation of said cable by said crankarm, a shearing head assembly remote from said frame, the opposite endof said sheath being fixed to said shearing head assembly, loppingshears comprising a pair of scissors, one blade of said pair beingfixedly mounted on said shearing head assembly, the opposite end of saidcable having extension means extending through said shearing headassembly and operatively attached to the other blade of said pair, drivelinkage means to drive said shaft, said shearing head assemblycomprising tube means, said cable extension means extending axiallythrough said tube means, and swivel connections in said shearing headassembly to enable swivelling movement of said opposite end of saidshearing head assembly with respect to the portion of said push-pullunit extending between said anchoring block and said shearing headassembly.

6. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, an anchor block fixedly supportedon said frame, a push-pull unit comprising an outer flexible sheathcapable of resisting substantial axial compressive stresses Withoutbuckling, and an inner cable loosely received in said sheath, one end ofsaid sheath terminating in a sleeve rigidly fixed to said anchor block,one end of said cable passing through said sleeve and extending towardsaid crank arm, means connecting said one end of said cable to saidcrank arm for reciprocation of said cable by said crank arm, a shearinghead assembly remote from said frame, the opposite end of said sheathbeing fixed to one end of said shearing head assembly, lopping shearscomprising a pair of scissors, one blade of said pair being fixedlymounted on the opposite end of said shearinghead assembly, the oppositeend of said cable having extension means'extending through said shearinghead assembly and operatively attached to the other blade of said pair,drive linkage means to drive said shaft, said drive linkage meanscomprising continuously driven means, clutch means between saidcontinuously driven means and said shaft, solenoid means on said frame,and means operatively connected to and controlled by said solenoid meansto engage said clutch means for one rotation of said shaft uponactuation of said solenoid means and to disengage said clutch means uponcompletion of said one rotation in the absence of continued actuation ofsaid solenoid means, switch means on said shearing head assembly tocontrol actuation of said solenoid means, and means operativelyconnecting said switch means and said solenoid means.

7. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, a push-pull unit comprising anouter flexible sheath capable of resisting substantial axial compressionwithout buckling, and an inner cable loosely received in said sheath,one end of 'said sheath terminating in a sleeve, means on said framerestraining said sleeve against axial shifting with respect to saidframe, one end of :said cable passing through said sleeve and extendingtoward said crank arm, means connecting said one end of said cable tosaid crank arm for reciprocation of said cable by said crank arm, ashearing head assembly remote from said frame, the opposite end of saidsheath being fixed to said shearing head assembly, lopping shearscomprising a pair of scissors, one blade of said pair being fixedlymounted on said shearing head assembly, the opposite end of said cablehaving extension means extending through said shearing head assembly andoperatively attached to the other blade of said pair, and drive linkagemeans to drive said shaft.

8. Power lopping shears comprising a frame, a shaft rotatably mounted onsaid frame, a crank arm on said shaft, a push-pull unit comprising anouter flexible sheath capable of resisting substantial axial compressivestresses 7 Without buckling, and an inner'cable loosely received in saidsheath, one end of said sheath terminating in a sleeve rigidly fixed tosaid frame, one end of said cable passing through said sleeve andextending toward said crank arm, means connecting said one end or" saidcable to said crank arm for reciprocation of said cable by said crankarm, a shearing head assembly remote from said frame, the Opposite endof said sheath being fixed to said shearing head assembly, loppingshears comprising a pair of scissors, one blade of said pair beingfixedly mounted on said shearing head assembly, the opposite '8 end ofsaid cable having extension means extending through said shearing headassembly and operatively attached to the other blade of said pair, anddrive linkage means to drive said shaft.

References Cited in the file of this patent UNITED STATES PATENTS1,713,444 Moore May 14, 1929 2,228,635 Ma'gennis Jan. 14, 1941 2,612,140Miller Sept. 30, 1952 2,613,437 McPhee Oct. 30, 1952

